Incinerator rotary kilns have an outside metallic shell, usually steel, the inside of which is fully covered by a thick ceramic wall, usually in the form of fire bricks having a total thickness exceeding in many cases 25 cm. These kilns usually operate at a exit gas temperature in the range of about 1,800.degree. to 2,400.degree. F. The ceramic walls, however, are very vulnerable to erosion and corrosion, due to the hostile conditions created by the nature of incinerated materials and high temperatures, especially, if alkali metals are present. If the viscosity of slag in the kiln is adequately high, it may form a rather thick viscous coating on the ceramic and thus protect it from the hostile environment. However, when the viscosity of the slag is very low, the slag contributes to the erosion and corrosion of the ceramic, both chemically because it serves as a solvent and mechanically, as it allows foreign big pieces of abrasive material to act against the ceramic walls. If the slag is viscous to the point of becoming substantially solid, or if it has never been formed as a liquid, it becomes ineffective in promoting combustion of organic matter, and also in capturing toxic heavy metals. Therefore, it is imperative that the viscosity of the slag is very carefully monitored and controlled within a range of values. Thus, one of the objects of this invention is to determine and correct the viscosity of the slag in rotary incinerating kilns.
Video cameras and other observation means have been used to inspect, different aspects of incineration chambers and other combustion devices. However, none of them deals with determining and controlling the viscosity of the slag in rotary incineration kilns by determining at least one property of slag drippings falling from the ceiling of the kiln, the properties including size of drippings, shape of drippings, aspect ratio of drippings, and number of drippings.
Our co-pending application Ser. No. 07/908,056, filed Jul. 6, 1992 (Byerly et al.), U.S. Pat. No. 5,228,398 which is incorporated herein by reference, describes methods and devices for controlling rotary incineration kilns by determining the position of the kiln outlet at which the slag is exiting.
Japanese Patent 57-84917, issued May 27, 1982 (Horie), describe a system, wherein an industrial TV camera is used to watch the terminating point of combustion of a garbage incinerator. The camera detects one by one the luminosities of combustion along a line intersecting at right angles with the transfer direction of the garbage. The camera, also detects the length of a portion on the line having a luminosity exceeding a predetermined level and compares it to a predetermined value.
Japanese Patent 59-1919, issued Jan 7, 1984 (Kojima), discloses a method, the purpose of which is to improve the discriminating accuracy of a combustion condition. This method is based on an image projected on a monitor, so that it automatically discriminates a combustion condition in an incinerator, and controls the combustion condition in the incinerator.
Japanese Patent 2-187510, issued Jul. 23, 1990 (Yoshii) discloses a method, the purpose of which is to make the incineration operation automatic, and make it possible to hold the point of complete burning of the refuge stable, by detecting optically the point of burning the dust in a combustion chamber and calculating the deviation from a control target and speed of movement of the result of detection, and then applying fuzzy inference to control the operation cycle or rotational speed of the combustion chamber.
Japanese Patent discloses a process, the purpose of which is to measure the temperature, the outflow speed, and an amount of outflow slug, and to perform rapid and proper processing without a time lag, so that discharge of slug is stabilized by a method wherein a slug outflow state is photographed by using a color TV and picture processing is applied thereon. In more detail, an industrial color TV is mounted in the vicinity of a slug tap, and in a data processing device, an input from the industrial color TV is always measured as a light three-original color output level through a filter in a four-division picture processing range, and a real time of temperature is measured, by means of a color tone. Regarding a slag outflow speed, the upper and lower parts of a four division picture are measured at intervals of 5 seconds, displacement in the slag flow is determined, and the outflow speed is also determined. Further, regarding an outflow slag amount, a change with time of the area of molten slag present in the four-division picture is trended at intervals of 5 seconds to determine a deviation in a steady value. By regulating an amount of enriched oxygen, an auxiliary fuel amount, and/or a sludge feed amount, molten slag is discharged in a stabilized state.
U.S. Pat. No. 4,361,032 (Lessnig et al.) discloses an apparatus for automatically determining the surface tension by the stalagmometer principle using a pipette containing a test volume, having a drop face at its lower end and is provided with three light barriers. The three light barriers are connected to an evaluation circuit which counts the number of whole drops and also determines the fractions of whole drops pertaining to the test volume.
U.S. Pat. No. 4,432,286 (Witte) discloses a pinhole camera system utilizing a sealed optical purge assembly which provides optical access into a coal combustor or other energy conversion reactors. The camera system basically consists of a focused-purge pinhole optical port assembly, a conventional TV vidicon receiver, an external, variable density light filter which is coupled electronically to the vidicon automatic gain control (agc). The key component of this system is the focused-purge pinhole optical port assembly which utilizes a purging inert gas to keep debris from entering the port and a lens arrangement which transfers the pinhole to the outside of the port assembly. One additional feature of the port assembly is that it is not flush with the interior of the combustor.
U.S. Pat. No. 4,646,562 (Cronan) discloses a method and apparatus for continuous monitoring of the relative dynamic surface activity of a liquid in which the surface activity can be rapidly changing is disclosed. The liquid is flowed through an orifice at a constant volume flow rate to produce liquid drops. The time intervals between successive drops from the orifice are measured. Variations in the time intervals of pairs of two successive drops provide an indication of the volume of the second drop of each pair and thus provide an indication of the relative dynamic surface activity of the second drop. The measured time intervals are converted into electrical signals which are representative of the respective measured time intervals. The method and apparatus can be applied to liquid chromatography separations to continuously and quickly provide information about surface active components of the liquid and is especially applicable when only a small volume of the sample liquid is available. The method and apparatus can also be applied to industrial process monitoring and to use as a general laboratory instrument or method.
U.S. Pat. No. 4,942,760 (Almeida) discloses an apparatus to measure interfacial tension of fluids in equilibrium and, more particularly, a liquid in equilibrium with a gaseous phase thereof using a pendant drop method, at superatmospheric pressure and elevated temperature conditions. The apparatus includes a visual cell having an interchangeable, multiple capillary injection system, a double-piston pump which permits the drop's injection into the cell without disturbing the experimental conditions, and an optical system comprising a photographic camera, a telemicroscope, and a lighting system.